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Darwin Correspondence Project

From John Scott   24 September 1867

Roy. Botanic Gardens | Calcutta

24th. Sept. 1867

Dear Sir,

I was much pleased to receive your letter by last mail though sorry when I had read it to think that I could do so little to meet your requests.1 Permit me to say however that I shall always continue proud to do my best: you can always command my services.

With respect to Vandellia, I am unfortunately ignorant of the species you want.— I do my best however, in the circumstances and enclose you fresh seeds of the only two species which I can find in our neighbourhood—2 Lately I have got a pretty species from Silhet, I expect to find a pod of this also to enclose for you.3 I may state however that I have seen no closed flowers on any of them—though there are a profusion of perfect flowers in the two common species. Possibly like Viola, they may produce closed flowers in another season. I shall look to them in the ensuing cold season—4

Since you wrote me, I have examined the genus in the Herbarium, and did not find a single species without perfect flowers. 5 As you ask me if ever I have seen Vandellia with perfect flowers, I append enumeration of the species I have examined   they may interest you and may possibly thus also hit upon the species which you have in view. I enclose list—all exhibiting perfect flowers—

Perhaps you might like a few seeds of our Viola Roxburghiana, Voigt., which I find produces perfect flowers in the cold season only; in the hot season a sparing number of imperfect, and in the rains a profusion of the same, all perfectly fertile. 6 I enclose seeds—and I shall later send you seeds of a new species, I had lately from the Sikkim Terai.7 This also produces some closed flowers only though the collector tells me he saw it in flower in its native habitats in February— the sexual economy is thus probably similar to above—

Leersia has not produced a single perfect flower with me: though I have now had it growing freely for upwards of two years. I am sorry I have no seeds of it by me just now—and there are only a very few unripe ones on my plants. I shall send you a few in time for sowing next spring. I have sent seeds of it to Darjeeling for cultivation and return of seeds. By such interchanges I do hope to effect a change in its sexual economy, though thus I have failed.8

Now for Adenanthera—which indeed is a perplexing case.9 When you wrote I could not think of ever having seen a bird touch the seed. Fortunately we have plants in the gardens covered with seeds now, & so have specially attended to it— — The seeds assume their rich scarlet hue and become quite hard previous to the dehiscence of pod, this taking place gradually from the apex and accompanied by the tortion of the valves, which internally are of a silky grey colour, and thus exhibit to advantage the pendent scarlet seeds. One can readily imagine what pretty objects large trees of this plant must form when covered (as I am told they frequently are in Molucca)10 with the dehisced pods, and the full number of seed (12) or more pendent from each— In trees in our Garden, I have only seen at any one time a few seeds in each pod exposed— The lower in apical seeds having always dropped off ere those in the basal part of pod had been exposed.

I had seen no birds touch the seeds until by the merest accident when passing one of the Small Sulphur-Crested Cockatoos—Cacatua sulphurea—belonging to Dr. Anderson.11 I showed it a few seeds of Adenanthera when it quickly alighted from its perch and picked a few from my hands, and with little difficulty split their hard testa, and eat with seeming gusto the embryonic parts only rejecting the coloured covering.

I next put the bird on a tree (seed bearing) of Adenanthera: it scrambled quickly up to where the seeds where, grasping the branch with one foot, it with the other caught the pendent pods; retaining this position until it had filled its bill with the exposed seeds then re-erecting itself it commenced the splitting process, which it does with facility by grasping a single seed in its foot and holding it in the concave extremity of lower mandible while it crushes it with the strong curved extremity of upper. You will readily understand the adaptability of the Cockatoos bill for such work—and in carrying the co-adaptation further— I may remark that the Cockatoo dislikes the unripe seeds, in general rejecting them. It shows no aptitude either in opening the pods, but usually drops them when it has picked out the exposed seeds—were it otherwise Adenanthera might soon be a rare plant in the haunts of Cockatoos; but as it is they are clearly a means for its dissemination. Thus as I have observed it generally takes several seeds into its bill before posing itself for the splitting and I invariably see that fully 50 percent of these are dropped uninjured while it splits the remainder.— — I can’t say whether the seeds, if swallowed accidentally by the Cockatoo would be passed unimpaired, however I find they are by the Common Fowl (G. domesticus).12 It naturally rejects the seeds, but I made the experiment by forcing a few thoroughly ripe and hard seeds on one, and a few unripe seeds on another— In the latter they were digested— in the former past uninjured.... The seeds of Adenanthera unlike those of many species of related genera e.g. Prosopis spicigera, Linn., several of the Ingas of which I may notice I. dulcis as one whose seeds are imbedded in a mealy pulp of which the Indian Crow is remarkably fond) are entirely destitute of any pulp.13

In conclusion allow me to refer to the apparent Co-relations which we at times observe between the colours of flowers and seeds, when variations occur in the former—14 Thus Canavalia gladiata, D.C. has varieties with flowers and seeds red & fls & seeds white, and also a variety (I must state) with a variation in the flowers (white) while the seeds continue red. Again, Abrus precatorius has vars. with rose-col. fls. & red seeds with a dark eye: white flowered var. greyish seeds with eye brown: and a second whitish flowered variety has black seeds with a white eye. Similar cases also occur in Dolichos sinensis; Lablab vulgaris etc—15 but I need not enlarge as you will no doubt be familiar with many such cases, and have fully considered their bearing on the case in point (Adenanthera)

Reflecting on such variations I had previous to the receipt of your letter, regarded, I believe too lightly the end to which colour in seeds may at times be subservient— The preeminent beauty of the Adenanthera is remarkable— I shall direct my observations more to the subject.

I am always keeping in view your queries about expression—16 I find it however most difficult to make exact and satisfactory observations— Several of the more simple, I am now prepared to answer you, however, as the time you gave me is yet far from expired I shall continue my observations, and send you them at once as complete as I can—17

I am glad to say that I am extremely comfortable in my position here—for which I feel ever thankful to you18 and remain | Dear Sir | Most respectfully yours | J. Scott

P.S. over I append list of Vandellias

List of Vandellias in which I have observed perfect flowers—

Vandellia mollis, Benth.— from my parts of India

— erecta Benth.— Do

— nummularafolia, D. Don. Do

— angustifolia, Benth— Do

— crustacea,—Benth Do

— molluginoides, Benth.

— multiflora, f. Don.

— scabra, Benth—

— laxa, Benth19

CD annotations

1.1 I was … failed. 5.6] crossed blue crayon
3.3 I append] after opening square bracket, red crayon
4.1 Perhaps … above— 4.7] ‘Violets’ in margin, red crayon
4.6 the sexual … years. 5.2] scored red crayon
6.1 Now] after opening square bracket, blue crayon
7.1 I had] ‘(About conspicuous seeds)’ added in margin above, blue crayon; square brackets in original


CD’s letter has not been found, but in a letter to Fritz Müller he mentioned that he had written to India to try to find out how Adenanthera seed was disseminated (letter to Fritz Müller, 15 August [1867]; see n. 9, below).
In Cross and self fertilisation, p. 90, CD reported having received seeds of Vandellia nummularifolia from Scott (see also Forms of flowers, pp. 324–5). The other species Scott sent has not been identified. Notes made by CD on 5 and 11 October 1868 recording experiments on V. nummularifolia are in DAR 111: 25–6. Notes comparing seed production of open and cleistogamic flowers of V. nummularifolia, dated 1 November 1875, are in DAR 111: 28.
Silhet was a city in eastern Bengal (now Sylhet, Bangladesh; Columbia gazetteer of the world).
CD was interested in species that produced closed (cleistogamic) flowers, which were invariably self-pollinated. For more on Viola in this context, see Correspondence vol. 13, letter from B. D. Walsh, 1 March 1865 and n. 12, and Forms of flowers, pp. 314–21.
The existence of open or ‘perfect’ (that is, non-cleistogamic) flowers in species that also produced closed flowers lent support to CD’s view that no species was perpetually self-fertilised (see Origin, pp. 96–101, and Orchids, p. 359). CD discussed the relation of cleistogamic to open flowers in Forms of flowers, pp. 335–45.
CD reported the results of his experiments with Viola roxburghiana (a synonym of V. patrinii) and cited Scott’s observations in Forms of flowers, pp. 319–20. CD’s notes on V. roxburghiana are in DAR 111: 18.
The new species referred to was Viola nana (a synonym of V. tricolor); CD reported receiving the seeds from Scott and discussed his observations on the species in Forms of flowers, p. 319. CD’s notes on V. nana are in DAR 111: 13. The Terai is a region of south Nepal and north India below the southern Himalayan foothills (Columbia gazetteer of the world).
Scott refers to experiments with the grass Leersia oryzoides; he had asked CD for seeds in 1865 (see Correspondence vol. 13, letter from John Scott, 21 July 1865). CD had published observations on Leersia in ‘Three forms of Lythrum salicaria’, pp. 191–2 n. (Collected papers 2: 131). In Forms of flowers, p. 335, CD reported sending seeds from cleistogamic flowers to Scott.
Scott refers to the fact that Adenanthera pavonina produces conspicuous seeds with no apparent nutritive value. See letter to Fritz Müller, 15 August [1867] and n. 11. For more on CD’s interest in this species and the dissemination of its seeds, see Correspondence vol. 14.
The Moluccas (now called Maluku) are an island group of eastern Indonesia between Sulawesi and New Guinea (Columbia gazetteer of the world).
The lesser sulphur-crested cockatoo (Cacatua sulphurea) is native to Sulawesi and many of the surrounding islands, where Adenanthera pavonina is also found (Birds of the world; Corner 1988, 1: 450). Thomas Anderson was the superintendent of the Calcutta botanic garden.
Gallus domesticus. For CD’s earlier experiment feeding seeds of A. pavonina to a fowl, see Correspondence vol. 14, letter to J. D. Hooker, 10 December [1866].
Like Adenanthera pavonina, Prosopis spicigera, and Inga dulcis (a synonym of Pithecellobium dulce) belong to the subfamily Mimosoideae of the family Leguminosae (Allen and Allen 1981). Scott refers to Corvus splendens, the house crow (Birds of the world).
CD discussed correlated variation of flower, leaf, and seed colour in plants in Variation 2: 330.
Scott refers to Canavalia gladiata, Abrus precatorius, Dolichos sinensis (a synonym of Vigna sinensis), and Lablab vulgaris (a synonym of Dolichos lablab).
CD evidently enclosed a copy of his queries about expression (for a printed version, see Correspondence vol.15, Appendix IV) in his letter to Scott (see n. 1, above), or in an earlier letter.
The printed version of the queries on expression suggested that answers be sent within about a year (see Correspondence vol. 15, Appendix IV). Scott sent his replies to the queries with his letter of 4 May 1868 (Correspondence vol. 16).
CD had helped Scott to find employment in India and had given him financial support (see Correspondence vol. 13, letter from John Scott, 20 January 1865 and n. 6).
Scott refers to Vandellia mollis, V. erecta (a synonym of V. multiflora), V. nummularafolia, V. angustifolia, V. crustacea, V. molluginoides, V. multiflora, and V. laxa (a synonym of V. scabra).


Sends seeds of Viola roxburgiana which produces perfect flowers in the cold season and imperfect ones in the rains, all perfectly fertile.

Leersia has not produced a single perfect flower though it grows freely.

Discusses cockatoos eating various seeds. Finds it difficult to make exact and satisfactory observations.

Appends list of Vandellia species which have perfect flowers.

Letter details

Letter no.
John Scott
Charles Robert Darwin
Sent from
Royal Botanic Gardens, Calcutta
Source of text
DAR 157a: 106
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 5633A,” accessed on 24 February 2019,

Also published in The Correspondence of Charles Darwin, vol. 15